Added Value of SPECT/CT to Whole Body Scan Test Planar Imaging in Patients with Thyroid Cancer After Radioiodine 131 Therapy

Abstract

Objective: The aim of this retrospective study was to determine added value of single photon emission computed tomography (SPECT)/computed tomography (CT) imaging to whole body scan (WBS) planar imaging in patients with thyroid cancer after radioiodine 131 ablation therapy.Methods: Indications for treatment of radioactive ablation therapy were postsurgical ablation, recurrent or metastatic disease with high thyroglobulin level of 50 patients with thyroid cancer were evaluated. Following 6 or 7 days after the between 50 and 300 mCi of radioiodine 131 administered orally in patients examined with WBS planar imaging, suspicion of metastasis evaluated with SPECT/CT imaging method. Imaging techniques were evaluated by nuclear medicine specialist with over 10 years experience in thyroid cancer management. The number of lesions assessed with planar images and the number of lesions assessed with SPECT/CT were recorded. The difference between the level of significance was tested using Wilcoxon Signed Rank test, SPSS 12 software package. Special cases with lesion based analysis was performed by examining the reviews.Results: On planar images 188 foci were detected, on SPECT/CT images 196 foci were detected. Difference between the number of detected lesions was found to be a statistically significant (p<0.05). SPECT/CT added diagnostic value 117 of 188 foci over planar imaging.Conclusion: In patients with thyroid carcinoma, there was a statistically significant difference between the number of lesions detected with WBS planar imaging and the number of lesions detected with SPECT/CT.